Frequency receiving bell with an



w. s. EATON Oct. 21, 1952 FREQUENCY RECEIVING BELL WITH AN ELASTICALLY YIELDABLE DIAPHRAGM EXTENDING ACROSS ITS MOUTH Filed l larch 17, 1947 Patented Oct. 21, 1952 FREQUENCY RECEIVING BELL WITH AN ELASTICALLY YIELDABLE DIAPHRAGM EXTENDING ACROSS ITS MOUTH Warren S. Eaton, Los Angeles, Calif. Application March 17, 1947, Serial No. 735,178

4 Claims. 1

This invention is a frequency receiving or collecting bell such as may be used upon a stethoscope or other frequency indicating means and has for its object to provide a new and improved bell which may be manipulated so as to select a frequency or frequencies from a plurality of frequencies and thence pass such selected frequency or frequencies for use or consideration.

It is also an object of the invention to compensate for pressure changes within the bell should such changes occur, as by negligent handling of the bell while using the same for frequency se lection.

The bell of the present invention is of general conical form or shape, is elastically yieldable so that by progressively pressing the bell against a source of frequencies its peripheral edge will move progressively outwardly and thereby automatically and progressively decrease the cubical volume and also the effective area of the mouth of the bell to facilitate selectively passing all frequencies within the limitation of the bell. lhe reverse effect will occur as application pressure is gradually removed from the bell and the latter progressively resumes its normal condition.

With these and other objects in view, the present invention consists in the combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it, of course, being understood that changes in the form. proportion, construction and minor details may be made, within the scope of the claims, without departing from the spirit or sacrificing any advantages of the invention.

In the drawings- Figure l is a longitudinal sectional view of a stethoscope bell embodying features of the present invention;

Figure 2 is a view showing the bell of Figure 1 in a collapsed condition;

Figure 3 is a view similar to Figure 1 showing a modification of the invention;

Figure 4 is a view similar to the bell of Figure 3 partially collapsed;

Figure 5 is a view similar to Figure 1 but showing a ribbed construction;

Figure 6 is a fragmentary view similar to Figure 1 and showing a diaphragm closing the open mouth of the bell;

Figure 6a is a view similar to Figure 1 showing a modified form of diaphragm;

Figure 7 is a view similar to Figure 6 and showing a different modification;

Figure 8 is an end elevation of Figure 7 looking at the diaphragm and showing a modification;

Figure 9 is a fragmentary top plan view of the bell showing venting means therefor;

Figure 10 is a longitudinal sectional view on the line I 9-! 0 of Figure 9.

Frequency selectivity is accomplished, according to the present invention, by manipulation of the bell A, and in carrying out this feature of the invention, the bell is constructed so that it may be conveniently and progresssively collapsed for the purpose of varying the cubical volume and also the effective area of the mouth of the bell. A satisfactory way of accomplishing this result is to make the bell A of rubber or other elastically yieldable material so that after the open mouth of the bell has been placed against a source of frequencies, the bell may be pressed against the body from which frequencies are emanating with the result that the peripheral edge of the open mouth of the bell will thrust outwardly across the surface of said body as in Figure 4 or curl or roll upwardly and outwardly as indicated in Figure 2, whereby the cubical volume and the area of the mouth of the bell will be decreased, thus gradually and progressively providing for passing selected frequencies through the bell, as will readily be understood. In other words, when the bell is in its normal condition as shown in Figures l and 3, the bell will be at its lowest fre quency receiving condition. By manipulating the body of the bell, as by pressing on the bell it may be gradually and progressively collapsed to its opposite or high frequency limit, as indicated in Figures 2 and 4. It will, of course, be understood that by progressively removing pressure from the bell, the latter will gradually and progressively resume its normal shape or condition thereby varying the frequency selectively in the reverse manner. The bell may be of any preferred shape or contour. As shown in the drawings, the small end of the bell terminates in a neck I) having a central longitudinal passage 0 opening at its inner end into the interior or chamber of the bell and opening at its outer end through the outer end of the neck.

The passage 0 provides for conducting frequencies away from the chamber of the bell. The outer end of the passage may be connected to a stethoscope tube, or other conducting means.

It will be noted that in Figures 1 and 2, the mouth of the bell is provided with an external annular integral bead e which stiifens the edge against expansion thereof and causes said edge portion of the mouth of the bell to roll or curl outwardly and upwardly during the collapsing of the bell. In Figures 3 and 4, however, the head is omitted, in which case the free edge portion of the bell is not stifiened and therefore will thrust outwardly along the surface to which the bell is applied.

In Figure 5 of the drawing, the exterior surface of the body of the bell is provided with a series of annular ribs d, such series extending from the peripheral edge of the mouth of the bell to about the base of the neck b, whereby an initial pressure will result in an outward movement and upward bending or curling of said edge of the bell. In practice, there will. be an appreciable stopping of the collapsing of the bell as each rib comes into contact with the subject, and thus the annular ribs constitute guage means for indicating the degree to which the bell has been collapsed, as distinguished from the more continuous progressive collapsing of a bell having a plain exterior as in Figures 3 and 4.

When using the bell on a person, the skin of the person constitutes an elastic diaphragm for the bell and stretches with the outward movement of the periphery of the mouth of the bell becoming thinner and tauter as the collapsing of the bell continues. However, the ability of the skin to stretch is limited and as such limit will be reached before the bell has been fully collapsed, the edge portion of the bell will continue to move outwardly without further stretching of the skin diaphragm.

In order that the complete selectivity of the bell may not be impaired by the presence of such non-stretchable skin diaphragm, I provide the bell, as in Figure 6, with an elastically yieldable thin diaphragm 25 which will continue to stretch and thereby become thinner and tauter as the bell collapses to its limit. The diaphragm does not interfere with the outward movement or rolling up of the peripheral edge of the mouth of the bell for the reason that the diaphragm will stretch and allow collapsing of the bell.

Where it is desirable to listen to high frequencies indicative of human body ailments, I provide for attenuating the low frequencies by the use of a dampening medium as for instance a concentric thickened portion of the diaphragm as indicated at 26 in Figure So. It will here be explained that as the bell is progressively collapsed and the diaphragm progressively stretched and thereby thinned, the thickened portion 26 will likewise be progressively stretched and thus progressively thinned, whereby the dampening effect of the part 26 is progressively reduced.

Simultaneously with the slow reducing of the low frequency dampening effect of the part 26, the thinning of the diaphragm, the increasing of the tension therein, the reducing of the area of the mouth and the reducing of the cubical volume of the bell will more rapidly improve the transmission of the high frequencies and thus intensify the reception thereof.

Instead of thickening the central part of the diaphragm, as in Figure 6, there maybe employed, as in Figures 7 and 8, a relatively thin rigid disc 28 disposed concentrically of an elastic diaphragm 21 which is of the same elastic thin thickness throughout. This disc may be mounted upon the inner face of the diaphragm as in Figure 8, or on the outer face thereof, as in Figu-re 9. In each instance, the disc is suitably secured to the elastic diaphragm'as by means of a, spotof cement or other suitable adhesive indicated at 28, in Figure 14, such cement being disposed at the center of the disc, the diaphragm being free of the disc all around the spot of cement and from the periphery of the spot to the connection of the diaphragm with the bell periphery. This form of diaphragm is for the same purpose as the diaphragm 25.

Should the pressure rise or fall within the bell, venting may be provided for in the manner shown in Figure 10, which is a longitudinal sectional view of the neck portion 19 of a collapsible bell A, such as has been shown in Figures 1 to 8, inclusive,'provided with venting means such as will now be described. In this form of venting, the neck of the bell is provided with a pair of similar bores 49 and 50 disposed at opposite sides of the passage c in said neck and opening at their outer ends through the outer end of the neck and at their inner ends through the inner end of the neck or through the wall portion of the bell at or near the inner end of the neck so as to form vent passages leading between the interior 'of the bell and the exterior thereof. As'shown, an outer portion of each bore is larger than an inner portion, thus forming an annular shoulder 5| facing outwardly. Within each enlarged bore portion there has been shown an open ended tubular valve casing 52 having its inner end bearing against the shoulder. A screw plug 53 is threaded into the outer end of each valve casing and provided with a vent opening or passage '54 extending longitudinally through the plug. Each plug may be provided with a screw driver notch, a wrench head not shown, or other means for turning the plug in applying and removing it. Each valve casing houses a helical spring 55. In one casing there is a valve member 55, shown as a ball, interposed between the outer end of the spring and the inner end of the plug and normally held yieldingly against the plug to normally close the passage therethrough. The opposite end of the spring bears against the shoulder 51 or shoulder provided within the valve casing, as shown. By this vent arrangement the valve will open under a reduction in pressure in the bell and thus ad mit atmospheric pressure for maintaining normal pressure in the bell. In the other valve casing, a valve member 57, such as a ball, is interposed between the inner end of the spring and the shoulder 5! as a valve seat or a valve seat provided at the inner end of the valve casing. The valve 51 is normally held closed by its spring whereby increased pressure in the bell will vent therefrom to the atmosphere.

To accommodate these vent valves, as shown in Figure 9, the neck c of the bell may be laterally enlarged or provided with external longitudinal integral ribs 58 through which the bores 49 and 50 are formed.

A somewhat simpler form of vent has been shown in Figures 1 and 2 in the form of a hole or passage 59 provided in the neck portion of the bell and extending therethrough and having open ends. This passage may be controlled by placing a thumb -or finger upon the outer open end of the passage to close the same during operation of the bell. By reducing the finger pressure, the passage may thereby be partially opened for venting purposes.

Having thus claim is:

l. A frequency receiving or collecting bell consisting of a conc'avo-convex body of elastically yieldable material having a mouth atone endand a neck at the opposite end thereoLsaid neck bedescribed my invention, what I ing provided with a longitudinal passage open at both ends and communicating from the interior of the bell body through the passage to the open outer end thereof, the walls of the bell body being free to collapse progressively from the mouth to the neck under the effect of pressure applied longitudinally of the neck, the marginal edge of the mouth being in one and the same plane, said bell being provided with an elastically yieldable diaphragm extendin across the mouth thereof.

2. A frequency receiving or collecting bell consisting of a concavo-convex body of elastically yieldable material having a mouth at one end and a neck at the opposite end thereof, said neck being provided with a longitudinal passage open at both ends and communicating from the interior of the bell body through the passage to the open outer end thereof, the walls of the bell body being free to collapse progressively from the mouth to the neck under the effect of pressure applied longitudinally of the neck, the marginal edge of the mouth being in one and the same plane, said bell being provided with an elastically yieldable diaphragm extending across the mouth thereof, said diaphragm having a central thickened portion.

3. A frequency receiving or collecting bell consisting of a concave-convex body of elastically yieldable material having a mouth at one end and a neck at the opposite end thereof, said neck being provided with a longitudinal passage open at both ends and communicating from the interior of the bell body through the passage to the open outer end thereof, the walls of the bell body being free to collapse progressively from the mouth to the neck under the effect of pressure applied longitudinally of the neck, the marginal edge of the mouth being in one and the same plane, said bell being provided with an elastically yieldable diaphragm extending across the mouth thereof, and a relatively thin rigid disc provided centrally on the diaphragm.

4. A frequency receiving or collecting bell consisting of a concavo-convex body of elastically yieldable material having a mouth at one end and a neck at the opposite end thereof, said neck being provided with a longitudinal passage open at both ends and communicating from the interior of the bell body through the passage to the open outer end thereof, the walls of the bell body being free to collapse progressively from the mouth to the neck under the effect of pressure applied longitudinally of the neck, the marginal edge of the mouth being in one end and the same plane, said bell being provided with an elastically yieldable diaphragm extending across the mouth thereof and having a relatively thin rigid disc provided centrally on the diaphragm, said disc being connected to the diaphragm at the center of the disc only, and the diaphragm being free to stretch from its connection with the disc to its connection with the bell.

WARREN S. EATON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 705,934 Knudson July 29, 1902 863,571 Kinter Aug. 13, 1907 1,157,428 Sheppard Oct. 19, 1915 1,321,266 Wilkinson Nov. 11, 1919 1,784,172 Bloch Dec. 9, 1930 2,225,509 Schober Dec. 17, 1940 2,258,743 Dax Oct. 14, 1941 2,336,669 Brown Dec. 14, 1943 2,456,346 Veneklasen Dec. 14, 1948 FOREIGN PATENTS Number Country Date 279,305 Great Britain Oct. 27, 1927 

